1. Field of the Invention
The present invention relates to a sputtering device, and more particularly, to a sputtering device with a gas injection assembly.
2. Description of the Related Art
In recent years, as cutting edge electronic devices, such as liquid crystal devices (LCD), become light and thin, components mounted in these devices also become smaller. So does the distance between adjacent components. In order to form a minute line between each component, various methods for forming a thin film have been proposed, for example a sputtering method. The sputtering method will be explained as follows.
First, a substrate on which a thin film is to be formed is loaded inside a vacuum chamber using a substrate transferring device. Then, a specific pressure and a voltage are supplied to an inactive gas inside the vacuum chamber, to generate a plasma around a target. Positive ions in the plasma formed around the target hit a surface of the target with an electric force. Also, the positive ions in the plasma transfer their kinetic energy to atoms on the surface of the target. When the transferred kinetic energy is greater than a bonded energy between the hit atoms, the atoms on the surface of the target are emitted from the target to be deposited onto the substrate.
FIG. 1 is a schematic view of a magnetron sputtering device according to the related art. Referring to FIG. 1, a sputtering device 1 includes a vacuum chamber 10, a vacuum pump 30 for maintaining a vacuum state inside the vacuum chamber 10, a supporter 40 for supporting a substrate to be sputtered, and a plasma generating unit 20 for generating a plasma in the vacuum chamber 10. The plasma generating unit 20 includes a target 21 formed of aluminum (Al), aluminum alloy (AlNd), chrome (Cr), molybdenum (Mo), etc., depending on the type of thin film to be formed, a cathode plate 23 for fixing the target 21, a magnet 25 for generating a magnetic field at rear surfaces of the target 21 and the cathode plate 23. The magnet 25 collects plasma between the target 21 and a substrate 29 into a periphery of the target 21, and increases the ion generating ratio on the target 21. The supporter 40 is provided with a supporting unit 27. The substrate 29 is transferred by a substrate transferring robot hand (not shown) to adhere and be fixed to the supporting unit 27.
An inactive gas, such as Ar, is injected into the vacuum chamber 10 of the sputtering device. Then, the inactive gas is discharged and excited into a plasma state, in which positive ions and negative ions are mixed together. Also, a DC pulse is applied to the cathode plate 23. Thus, a negative high voltage is applied to the target 21. Ionized inactive gas (Ar+) is accelerated towards the target 21. Because the ions accelerated towards the target 21 have more than several tens of KeV of kinetic energy, the ions partially transfer their kinetic energy to atoms on the surface of the target when they collide with the target 21. The atoms on the target 21 are freed from the surface of the target 21 in the form of negative ions. The negative ions from the target 21 are quickly deposited onto the substrate 29 by an electric field and a magnetic field, and form a film on the substrate 29.
However, in the related art sputtering device, the substrate and the supporter are fixed to each other. The contact between the rear surface of the substrate and the supporter may cause a back scratch, or cause the substrate to break. Especially, during loading or unloading of the substrate into/from the vacuum chamber, when the substrate goes through a region where the vacuum state is replaced by an atmospheric state, the entire substrate is not constantly moved due to an unstable air stream. Accordingly, the substrate may be damaged. Moreover, in the related art sputtering device, a substrate that has been horizontally transferred by a substrate transferring unit, such as a robot hand, is again transferred onto a substrate supporter inside a sputtering chamber.